PL104768B1 - CURING COATING AGENT - Google Patents

Description

The patent description was published: 01.12.19791 104 768 liquid, there are a number of important potential applications in which its rate of transformation in the solid product is too small. A common trade-off is to build in important strings self-oxidizing fatty acids from oil to oil-modified alkyd or epoxy ester usually with a molecular weight above 3000 and accepting the need to use of such products in solutions of volatile organic liquids, obtaining in return much faster speed curing. Thanks to the introduction of an alkyd structure into which other reactive groups can be incorporated, Chemical reactions other than auto-oxidation may occur to accelerate curing. A similar solution, z similar advantages and disadvantages are the replacement of the alkyd structure in the oil-modified resin by a vinyl or acrylic polymer, usually with a molecular weight of about 10,000 or higher, with which the self-oxidizing fatty acid chains are covalently linked.

It has now surprisingly been found that it can be produced in contrast to these known methods self-oxidizing layers, transforming into hard coatings under the mild curing conditions used in the paint industry, if a coating agent with appropriately selected ingredients is used, w in which the film-forming component has a much lower molecular weight than the typical self-oxidizing polymer for these purposes. Thus, the coating agent is either immediately in a liquid form suitable for under conventional conditions, or easily brought to a consistency by addition a small amount of volatile solvent.

According to the invention, the self-curing coating agent is characterized in that its component the film-forming agent is a mixture a) a component containing an average of 1-2 epoxy groups in a molecule of the maximum average weight molecular weight 1200, b) a component having a maximum average molecular weight of 1000 containing on average every at least one carboxyl group and, on average, at least one other group in the molecule, a different group there is a carboxyl or hydroxyl group, c) a cross-linking agent containing at least two groups in the molecule that can react with the groups hydroxyl and d) an auto-oxidizing component selected from the group consisting of an auto-oxidizing monocarboxylic acid fatty and self-oxidizing monohydric fatty alcohol, constituting 0-50% by weight a mixture, the components (a-d) present in the mixture in such proportions that the ratio the total number of epoxy groups in component (a) up to the total number of carboxyl groups in the mixture ranges from 1: 0.5 to 1: 3.0, the total content of the components (a, b and d) in the mixture is 50-96% and the mixture contains 10-70 wt.% of auto-oxidizing fatty residues, and in addition the listed ingredients are selected from those substances which do not boil and do not undergo thermal decomposition below 180 ° C.

Ingredient (s) may be a simple compound or a mixture of compounds, provided that it complies with the above given requirements. It is therefore possible that one or more of the components have a molecular weight more than 1200, but the maximum average molecular weight does not exceed 1200. It is possible, for example, to component (a) contained 20 wt. substances with a molecular weight of 1500 and 80 wt. substance about the weight molecular weight of 1000, because the total average molecular weight will be 1100, which is given limits.

Typical examples of ingredients (a) are substances belonging to the group of commercially available diepoxy dicyclic acid ester of hexahydrophthalic anhydride and the reaction products of 2,2-di (p-hydroxyphe- nyl) propane (known as bisphenol A) from epichlorohydrin, e.g. known under the trade name "Epikote".

Ingredient (a) may also belong to the group of monoepoxides such as the monoester obtained by a dipoxide of the above-mentioned type with a monocarboxylic acid, such as e.g. acetic acid, propionic or caproic and auto-oxidizing fatty acids derived from nature vegetable oils such as castor oil, dehydrated castor oil, safflower oil, linseed oil and tung oil.

A preferred compound of this type is the monoester of the self-oxidizing monocarboxylic fatty acid i the diglycidyl ether of bisphenol A. The monoester may also be the glycidyl ester of the monocarboxylic acid him. Typical examples of such relationships are the products commercially available under the trademark "Cardura".

These are compounds of formula R * COOCH2 CH (O) CH2, in which R is an aliphatic hydrocarbon radical of Branched chain with 8-10 carbon atoms. Other products that can be used are epoxidized oils, i.e. naturally occurring triglycide oils in which part of the double bonds it was transformed into epoxy groups by reaction with peroxides.

Component (b) has a maximum average molecular weight of 1000 and contains on average at least one a carboxyl group and at least one other group on the molecule, said other group being a group 104 768 3 carboxylic or hydroxy. Ingredient (b) may be a simple compound or a mixture of compounds similar to component (a). Suitable substances are e.g. dicarboxylic acids, e.g. fatty acid dimer such as "Emery" 3393D (tradename) and the product of equimolar reactions amounts of maleated auto-oxidizing neopentyl glycol monocarboxylic acid; hydroxy acid sy such as ricinoleic and salicylic acid; tricarboxylic acids, e.g. the reaction product of equimolar amounts maleated self-oxidizing monocarboxylic acid and ricinoleic acid, maleated compounds self-oxidizing, e.g. maleated fatty acid from linseed oil, maleated 1,4-cis-polybutadiene and acid anhydrides, e.g. dodecenyl succinic anhydride and hexahydrophthalic anhydride. of the invention it is believed that the ring of the acid anhydride corresponds to two carboxyl groups.

The above examples are given merely to illustrate the essence of the invention and should not be taken in any way understood as limitations of its scope.

It is obvious to those skilled in the art that some of the ingredients (a) will react more slowly with some of the permissible ingredients (b) than with the others. For example, component (b) whose reactive groups are only the ring of the anhydride acidic acid, will not easily react with some dipoxid plants in the absence of active hydrogen. As a result therefore the reaction of such components (b) with these two epoxides will be very slow. They are understandable these are slow-reacting combinations and can therefore not be used or be activated before use suitable catalyst.

Ingredient (c) is a cross-linking agent containing at least two functional groups in the molecule that react with hydroxyl groups. This ingredient can be selected from a known group of products that act as agents cross-linking substances containing hydroxyl groups. Typical examples of ingredients (c) will be react with hydroxyl groups at annealing temperatures of the row, e.g. 170 ° C, there are urea resins and melamine-formaldehyde. A particularly useful and preferred compound of this type is methylolmelamine containing 4-6 methylol groups in the molecule, essentially completely etherified with methanol, or ethanol. Typical examples of commercially available cross-linkers of this general type are products known by the proprietary name "Cymel" 300 and 301 (hexomethoxymethylmelamine).

Alternatively, it may be desirable that component (c) react at lower temperatures than usual the annealing temperatures used. In such cases, for example, multifunctional isocyanates can be used.

One group of such measures is available under the proprietary name "Desmodur". Measures of this type that are easily react at ambient temperature, they are used as "multi-component compositions", i.e. systems whose the individual ingredients are stored separately and mixed just before coating.

Ingredient (d) is a substance selected from the group consisting of self-oxidizing monocarboxy fatty acids. xylic and self-oxidizing monohydric fatty alcohols. Self-oxidizing monocarboxylic acid fatty acid can be ricinoleic acid, linolenic acid, linoleic acid, oleic acid or an ester of such acid fatty acid with a hydroxy acid, e.g. 12-hydroxystearic acid. Alternatively you can also use mixtures of fatty acids, e.g. mixed fatty acids from the nature of triglycide oils, such as dehydrated castor oil, safflower oil, soybean oil, linseed oil, tung and tall. The self-oxidizing fatty alcohols that can be used as ingredient (d) are reduction products of the above-mentioned auto-oxidizing fatty acids. A typical example is "Assess" a commercially available alcohol containing an auto-oxidizing chain of 18 carbon atoms. it is necessary to mix monohydric alcohols and monocarboxylic acids to obtain an ingredient (d).

The individual components of the curable coating agent must be mixed in the above-mentioned proportions, if you want to get a coating with satisfactory properties. It was found that if e.g. ratio of the total number of epoxy groups in component (a) to the total number of carboxyl groups in the mixture is outside the range of 1: 0.5 to 1: 3.0, then the produced surface films are as soft and have too little mechanical strength to be of practical use.

In addition, some directions of property changes within these general ranges were observed. Especially it has been found that, however, coatings suitable for certain applications may be obtained at a ratio below 1: 1.5, as it approaches the 1: 3.0 limit, there is a gradual decrease in the hardness of the film. For this reason for best results it is recommended that the ratio of the total number of epoxy groups in for component (a) to the total number of carboxyl groups in the mixture is from 1: 0.5 to 1: 1.5. -70% of the self-oxidizing substituents can be entirely derived from self-oxidizing monocarbons xyl fatty acids and alcohols of ingredient (d). In the case of the present invention, "auto-oxidative residues "mean self-oxidizing unsaturated hydrocarbon chains excluding any groups at the end of a chain or any residue of such groups as a result of them reactions with other groups. For example, in the case of an auto-oxidizing acid or a fatty alcohol corresponding to 4 104 768 no carboxylic and hydroxyl flu fluids are taken into account. In the case of maleinated aamoutleniiijace- % o lanewha ns to treat such a chain as if it were not a small one. In another case, the remaining trsy the ingredients may contain a sufficient amount of self-oxidizing substituents and component (d) may not be needed, The auto-oxidizing substituents in the film-forming component are allowed to come from both tydhirddol.- It has also been found that, in order to provide suitable features for the agent of the invention, none of the inputs its components should not spindle or decompose below 180 ° C. It turned out that A coating with ingredients that do not meet this specification will make the coatings too soft.

The film-forming component is produced by mixing the selected ingredients in the usual way. If the ingredients are completely miscible, usually a simple mixing operation is sufficient. However, if some immiscibility is observed, it may turn out that to obtain the desired stability it is necessary the use of a known method of introducing into the composition a certain amount of co-solvent ka. However, since this usually results in a reduction of the total non-volatile (dry) content mats) in a coating agent, if a coating agent with a very high dry matter content, it is recommended to limit the choice of ingredients to such substances that are mutually exclusive soluble. A special feature of the invention relates to the selection of the ingredient, especially in terms of the upper limit molecular weight, makes many compositions so low in viscosity that they can be used at a dry matter content exceeding 80% by weight. This property is especially valuable because of material savings and air pollution.

The film-forming component can easily be converted into a coating agent in a known manner. If e.g. the coating is to be transparent varnish, the film-forming component itself, possibly with the addition of a catalyst, maybe be sufficient material. On the other hand, the usual additives can be dispersed or dissolved in it, e.g. pigments, driers, preservatives and other auxiliaries, making them opaque and / or tinted coating agent.

The curable coating agent according to the invention can be applied to a substrate using e.g. brushing or rolling, dipping or spraying. You can make a fresh film into a hard coating eg by leaving it to air dry at ambient temperature. Curing can be beneficial accelerate by heating and / or adding to the catalyst mixture.

The invention is illustrated by the following Examples in which all parts are given in units by weight.

Example I. Preparation of a coating according to the invention. The film-forming component is mixture of monoepoxide with a molecular weight of 680 (component, 65.2%), two hydroxy acids with average molecular weight 290 (component b, 25.8%) and hexamethoxymethylmelamine (component c, 9.0%). The component d is not present. The ratio of the total number of epoxy groups to carboxyl groups w of the film forming mixture is 1: 1.2, the total content of the a + b components is 91 wt.%. mixtures, which contains 41% self-oxidizing residues.

The following ingredients are ground to a fineness of 10-15 microns (as measured by Hegmann's instrument): weight parts Dioxectite 729 barites 2344 silica 26 anti-chafing agent * 20 Antimorillonite based anti-sedimentation agent 15 monoepoxide (reaction product of equimolar amounts of "Epikote" 828 ** and fatty acid from linseed oil) acetate-butyl 500 * r The technical 2,6-two-tertiary butyl-4-methylphenol is titrated.

** Condensation product of bisphenol A and epichloroliydrin with epoxy equivalent from 190 to 210 The following ingredients were then mixed until homogenized: weight parts suspension (prepared as above) 3824 monoepoxide (as above) 838 ricinoleic acid 370 Citric acid 37 "Cymel" 301 • 142 methyl ethyl ketone 444 • The sixth toxin to the turf 104 768 5 The film-forming component is: weight parts monoepoxide 1028 ricinic acid 370 citric acid 37 "Cymer301 142 The above coating composition contained a non-volatile portion of about 83 wt.%. after diluting it to obtain a viscosity suitable for application by spraying.

Example II, The preparation of a coating according to the invention, in which the film-forming component is it a mixture of monoepoxide with a molecular weight of 680 (component a, 59.7%), tricarboxide with an average molecular weight of 680 (component b, 29.85%) and hexamethoxymethylmelamine (component c, 10.45%). The component d is not present. Ratio of the total number of epoxy groups in component a until the total number of carboxyl groups in the mixture is 1: 1.5, the total weight of components a + b makes up 90 wt.%. a mixture that contains 41% self-oxidizing residues.

The procedure was similar to that in example I, with the difference that the substances of the film-forming component of which in this example have been replaced by the following substances: weight parts monoepoxide (as in Example I) 1028 tricarboxylic acid (reaction product of equimolar amounts ricinoleic acid and maleated fatty acid from steel oil) 514 "Cymer301 180 The resulting coating composition contained non-volatile portions of about 83% when diluted to obtain a viscosity suitable for application by spraying.

Example III. The example compares the behavior of the coatings with the agent according to invention and ordinary coatings. The coating compositions of Examples I and II were used as a primer under thermosetting acrylic enamel.

For comparison, a commercially available epoxyester car primer was tested.

The coating compositions of Examples I and II and the epoxyester primer were sprayed onto the galvanized, phosphated steel, to a dry sheet 25-30 microns thick, then annealed at 177 ° C in an air dryer for 25 minutes. The plates were then coated with a 40 micron layer (dry film thickness) of commercial acrylic enamel and baked for 30 minutes in an oven at 130 ° C. Discs was subjected to the following tests: a) Determination of the adhesion of the primer to metal. The study was carried out in accordance with the measuring test BI 6-1 Lot A by Ford Motor Company, one of many well known methods. It covers scratching the coated plate, sticking a strip of adhesive tape, and then tearing it off. Adhesion is judged by the amount of paint remaining on the scratches. b) Determination of the adhesion of the top coat to the primer. The study was conducted in accordance with the test Ford BI 6-1, part B, but the scratches do not go to the metal, but only to the base. c) Testing the resistance to gravel impact. In this test, the disc is suspended vertically in the unit measuring (gravelometer), and then bombards 400 g of fresh gravel blown onto the surface in the air stream at a pressure of approx. 6.3 kg / cm2. The bombing lasts 10 seconds. Coating the paint on the plate is assessed on a scale from 1 to 10, in which 10 corresponds to no damage and 1 to complete chipping pints of paint. d) Measurement of the impact resistance. The measurement was carried out as described in the requirement 20/38, Lot 4 (a) of Chrysler Australia Ltd. The plate is subjected to an impact force of 11.1 kgm, followed by the number of cracks formed is assessed. e) Measurement of flexibility. The measurement method is identical to that of the Ford BI 5-1. Plate it bends 180 ° on a conical mandrel and fixes the crack in the film. Blone is rated on a flexibility scale from 1 to 5, with 5 being the best and 1 being the worst. f) Measurement of resistance to salt spray. This measurement was performed as specified in the Measurement Method Ford BI 3-1 with the exception that the test was conducted for 350 hours. Along the longitudinal axis of the plate a plot is made through the sheet to the metal surface, before and after the measurement.

The degree of corrosion is measured in millimeters from the scratch. 6 104 768 Measurement of resistance to moisture. This measurement was performed as described in the Ford Measurement Method BI 4-2, with the exception that the measurement temperature was increased from 43 ° C to 60 ° C, thus the test was sharper. The plates were exposed to a high-humidity atmosphere in a Cleveland air-conditioning chamber within 240 hours. The chipping rate was measured by the method given in the "Exposure Standarts Manual", Federation of Societies for Paint Technology. This guide assesses the size of the spatter on an agreed scale from 10 to 0 (10 corresponds to no spatter) and the frequency of their occurrence in the following ranks: D (high), MD (medium-high), M (medium) and F (low).

The following results were obtained: Commercial Composition Composition epoxy primer of Example 1 of Example II a) metal adhesion excellent excellent excellent b) intercoat adhesion good good good (c) gravel resistance 9 9 9.5 d) impact strength moderate cracking moderate cracking moderate cracking e) flexibility 3 5 4 f) salt spray test (mm) 1 1-2 1 g) moisture resistance 8M 8M-8D 8F Based on the results, it can be concluded that the properties of the commercial epoxy resin primer and the compositions of both examples are similar. The compositions according to the examples, however, have the advantage that they can be applied with a dry matter content of 83% by weight, while the epoxyester primer can be applied only at a dry matter content of around 45% by weight.

Example IV. The example shows various coating compositions according to the invention obtained with different substances as component (a). Example II was repeated with the exception that 1028 parts of the monoepoxide in the film-forming component were replaced successively by: 1) 1028 parts of monoepoxide obtained by esterification of "Epikote" 828 with an equimolar amount of fatty acid from dehydrated oil of castor, 2) 1028 parts of monoepoxide obtained by esterification of "Epikote" 828 equimolar amounts fatty acid from soybean oil, 3) 1055 parts of monoepoxide obtained by esterification "Epikote" 828 equimolar amounts of ricinoleic acid and 4) 302 parts of epikote 828.

In all cases, the pigments and the appropriate portion of the film-forming composition were mixed in the mill ball. Thereafter, liquid coatings were prepared and applied to a steel substrate and tested as in example III. Properties similar to those of the coatings in the composition were obtained in all cases described in example II.

Example V, illustrating the coating agent according to the invention, in which different are used substances as ingredient (b). The example U was repeated with the difference that the tr (-carboxylic acid (514 parts) constituting component (b) of the film forming composition has been replaced by: 1) 514 parts of a tricarboxylic acid obtained by esterification of ricinoleic acid an equimolar amount of maleated fatty acid of linseed oil, 2) 287 parts of maleate fatty acid of linseed oil obtained by equimolar reactions the amount of fatty acid of linseed oil and maleic anhydride, 3) 435 parts of dicarboxylic acid obtained by esterification of neopentyl glycol eq molar amount of maleic fatty acid of linseed oil, 4) 493 parts of dicarboxylic acid obtained by esterification of citric acid by equimolar by the amount of glycidyl ester with a branched aliphatic chain, having a molecular weight of 245 (the commercial product known as "Cardura" E, manufactured by Shell Chemical Co. "Cardura" was used E is a glycidyl ester of an aliphatic fatty acid ^ in which the aliphatic part is a chain branched with 8-10 carbon atoms) and ) 635 parts of fatty acid dimer (the commercial product "Empol" 1022 was used as a dimer fatty acid with 36 carbon atoms).

Thereafter, liquid coating compositions were prepared as in Example II, annealed and tested as in example III. The results were similar to those of the composition of Example II.104 768 7 Example VI, illustrating the coating compositions of the invention in which various were used substances as ingredient (c). Example II was repeated with this equation, with 180 parts of the "Cymer 301" replaced sequentially by: 1) 300 parts of butylated urea formaldehyde resin with a content of 60 wt. non-volatile parts, 2) 300 parts of butylated malamine-formaldehyde resin with a content of 60 wt. flightless parts i 3) 225 parts of methylated melamine-formaldehyde resin with a content of 80 wt. non-volatile parts (The product used under the trade name "Uformite" MM-83 manufactured by Rohm and Haas was used.

The coatings were tested with the general method given in example III and found to have properties similar to coatings of the composition described in Example II. However, it has been found that the solids content of the composite spray application lives were reduced by about 8% when using substances (1 and 2) and by about 5% in the case of substance (3) than in the case of the composition of example II.

Example VII. This example compares the coating compositions that were changed ratio of the total number of epoxy groups in component (a) to the total number of carboxyl groups in mixture. Example II was repeated with the difference that instead of 514 parts of tricarboxylic acid, it was introduced 137, 274, 600, 767, 933 and 1066 parts of it respectively. This corresponds to the ratio of the epoxy groups to carboxylic acid 1: 0.4, 1: 0.8, 1: 1.8, 1: 2.3, 1: 2.8, 1: 3.2. Coating compositions were prepared as in example II, and then annealed and tested as in example III. The test results showed that coatings in which the ratio was 1: 0.4 and 1: 3.2, and therefore outside the scope of the invention, were unsatisfactory as the membranes were unacceptably soft and not suitable for further study.

The remaining compositions with the said ratio within the scope of the invention will retain collapsed properly, although the results of their tests were slightly worse compared to the results obtained for the coatings of the compositions described in Examples I and II. At ratios less than 1: 1.5, you get a film gradually getting softer.

Example VIII. The example shows the compositions according to the invention, in which the component (d) is the fatty acid of linseed oil. Example II was repeated with the exception of the amount of acid of the tricarboxylic acid was reduced to 308 parts and 254 parts of flaxseed fatty acid were added, which % was 14.4 wt. a film-forming component. Compositions were obtained from such a film-forming component as in example II which was tested according to the methods given in example III. The shell was supposed to properties similar to the coating of the composition described in example I.

Example IX. The example presents the preparation and test results of spray enamel general industrial use from the compositions according to the invention. Coating compositions were obtained by grinding until obtaining a suspension with a particle size of less than 5 microns (measured with a Hegman), the following ingredients: monoepoxide * titanium dioxide n-butyl acetate toluene weight parts 36.05 , 81 4.51 4.51 * Reaction product of equiniolar amounts "Epikote" 828 and ricinoleic acid.

Then the suspension was stirred until it was homogenized with a 77.4% solution of the dicarboxylic acid - lemon (Cardura - trade name) in n-butyl acetate, 6.86 parts by weight, monoepoxide obtained as above in the amount of 11.25 parts by weight, Cymel 301, in the amount of 7.34 parts by weight, xylene, 12.50 parts by weight and u-butyl acetate in the amount of 4.17 parts by weight. Film-forming component constituted: weight parts monoepoxide (described above) 47.30 citric acid (CarduraE) 6.86 "Cymer 301 (described above), 7.34 The ratio of the total number of epoxy to carboxyl groups was 1: 0.68 and the total weight of components a + b accounted for 88% by weight of the mixture which contained 26.6% by weight of auto-oxidizing residues people. The resulting coating composition had about 72% by weight of non-volatile parts and was viscous seconds (measured with Ford Cup # 4 at 25 ° C). The electric resistance of the composition was 2 Ohm. 8 104 768 The above compositions were tested as follows. Steel plate treated with phosphate of zinc coating, the coating compositions were applied by spraying to a film thickness of 30-35 microns, then it was baked at 150 ° C for 15 minutes. After cooling, the plate was subjected to the following tests: Score scleral 3-4 H. HardnessKnoopa 8-10 ("Tukon" hardness tester) gloss, measured at 60 ° 60% test on a taper mandrel 100% transition The test results show that the composition is satisfactory industrial enamel, which can be applied with a much higher content of non-volatile ingredients than the known enamels, which mostly contain parts non-volatile amounts are in the order of 45% by weight.

Claims (2)

Patent claims 1. A hardenable coating agent, characterized in that its film-forming component is a mixture of a) a component containing an average of 1-2 epoxy groups in a molecule with a maximum average molecular weight of 1200, b) a component having a maximum average molecular weight of 1000, containing at least one average molecular weight carboxyl and, on average, at least one other group in the molecule, the other group being a carboxyl or hydroxyl group, c) a cross-linking agent containing at least two groups in the molecule that can react with hydroxyl groups, and d) an auto-oxidizing component selected from the group consisting of a self-oxidizing fatty monocarboxylic acid and a self-oxidizing monohydric fatty alcohol, constituting 0-50% by weight of the mixture, where the components (a-d) are present in the mixture in such proportions that the ratio of the total number of epoxy groups in component (a) to the total number of carboxyl groups in the mixture is in the range is from 1: 0.5 to 1: 3.0, the total content of the components (a), (b) and (d) in the mixture is 50-96% by weight, and the mixture contains 10-70% by weight of auto-oxidising fatty residues, and the listed ingredients are chosen from those substances which do not boil and do not decompose thermally below 180 ° C. 2. The measure according to claim The process of claim 1, wherein the ratio of the total number of epoxy groups in component (a) to the total number of carboxyl groups in the mixture is from 0.5 to 1.5. Wash. Typographer. UP PRL, circulation 120 + 13 Price PLN 45